Instrument mounting

ABSTRACT

The particular embodiment described herein as illustrative of one form of the invention utilizes, in an instrument for lowering into a wellbore, an indicator device mounted in an inverse position in the instrument for measuring angular parameters of the wellbore, and a camera unit for recording the indicator measurements. The indicator is positioned above the camera in a fluid environment and on a pivotal surface with the indicator face pointing down. In order to permit a high angle of operation of the instrument, the pivotal surface is movable with respect to the indicator so that the pivot does not restrict the movement of the indicator for measurements in wellbores having an inclination up to 90*.

United States Patent [.94

Lichte, Jr.

[54] INSTRUMENT MOUNTING [75] Inventor: Henry P. Lichte, Jr., Houston,Tex.

[73] Assignee: Sperry Sun Well Surveying Company, Sugar Land, Tex.

[22] Filed: Y Apr. 6, 1970 [21] Appl. N0.: 26,044

Related U.S. Application Data [63] Continuation of Ser. No. 778,491,Nov. 25, 1968,

abandoned.

[52] U.S. CI. ..33/304', 33/365, 33/391 [51] Int. Cl. ..G0lc 17/02 [58]Field of Search.....33/222, 205.5, 205.5 P, 205.5 E,33/206, 206.2,215.1, 215.2

[56] References Cited UNITED STATES PATENTS 2,364,908 12/1944 Miller..33l222 2,357,586 9/1944 Greaves ..33/2l5 1 Apr. 3, 1973 2/l940Culbertson 2/1959 Rieger [57] ABSTRACT The particular embodimentdescribed herein as illustrative of one form of the invention utilizes,in an instrument for lowering into a wellbore, an indicator devicemounted in an inverse position in the instrument for measuring angularparameters of the wellbore, and a camera unit for recording theindicator measurements. The indicator is positioned above the camera ina fluid environment and on a pivotal surface with the indicator facepointing down. In order to permit a high angle of operation of theinstrument, the pivotal surface is movable with respect to the indicatorso that the pivot does not restrict the movement of the indicator formeasurements in wellbores having an inclination up to 90.

16 Claims, 3 Drawing Figures BACKGROUND OF THE INVENTION This inventionrelates to a mounting for a wellbore instrument, and more particularlyto an instrument mounting arranged to permit high angle operations inwellbore.

Wellbore instruments and tools inherently have' design limitationsassociated with the small diameter environment of the wellbore requiringa small diameter housing of short length to facilitate the movement ofsuch tools in the wellbore which often follows a tortuous path.Therefore, in order to avoid sticking the tool in the wellbore, it isdesirable to utilize a sho small diameter tool.

In addition, it is desirable to utilize one tool component for more thanone function where possible to facilitate size limitations and tominimize construction costs. For example, in an instrument makingmeasurements of more than one wellbore parameter, a'device may beutilized for recording all the measurements on one device.

In the drilling of boreholes into the earth, it is often desirable tosurvey one or more locations in the borehole to determine the angle anddirection of the hole. The hole may be cased or uncased and dependingupon this factor, it is often necessary to run various types ofinstruments simultaneously, and to make downhole records of themeasurements of such instruments for retrieval to the surface. Forexample, if it is desirable to measure and record the direction andinclination of a borehole which had been cased with metal pipe, agyroscopic instrument can be run into the wellbore, together with aninclinometer to measure the desired characteristics of the wellbore. Inorder to meet the size limitations of such an instrument, it isexpedient to use a single camera unit for recording the instrumentmeasurements by mounting one of the instruments at each end of thecamera unit.

An apparatus presently used for making such measurements includes agyroscopio instrument at the lower end of the tool above which ismounted a camera. Above the camera is mounted an inclinometer anddirectional indicator. The inclinometer is comprised of a rotatablewheel mounted on a movable shaft coaxial with the longitudinal axis ofthe tool housing. A weighted member on the shaft is aligned with thewheel for maintaining the wheel in a vertical orientation. A weight onthe indicator wheel will seek the bottom side of the wellbore. lndiciaon the wheel, when photographed, provide a record of the boreholeinclination at that instant. In the instrument just described, it isfound that at low angles of inclination, the weighted member on theshaft is not sensitive enough to overcome inertia in the device, so thatat low angles, the apparatus is ineffective to make accurate readings.

Another conventional inclinometer which is presently being used is sosupported by buoyant fluids as to provide for movement of its indicatorportion through an arc of 180, thereby providing reading of 90 ofinclination in any direction. However, when this apparatus is inverted,as for example to be used in the instrument described above whichrecords two instrument readings with a single camera, the buoyancyforces of the fluid and arrangement of the support for the floatingindicator will not permit free movement of the indicator over a widearc. Even when operated in an upright position, the floating indicatorarrangement is sometimes inaccurate due to sticking of the indicator onthe sides of container holding the buoyant fluids.

It is therefore an object of the present invention to provide a new andimproved mounting for a wellbore indicator apparatus.

SUMMARY OF THE INVENTION With these and other objects in view, thepresent invention includes, in a wellbore instrument, a housing formounting an instrument for indicating parameters of the wellbore and arecording unit for providinga record of the instrument readings. Theinstrument indicator face is mounted opposite a recording unit in thetool housing. The indicator is buoyantly mounted within the housing sothat it may move through an arc of 180 thereby providing readings in anydirection up to A pivotal member for supporting the buoyant indicator isarranged to move relative to the housing in response to gravity forcesso as to provide maximum clearance of parts at all times, and therebypermit such arcuate movement of the indicator within the housing.

A complete understanding of this invention may be had by reference tothe following detailed description when read in conjunction with theaccompanying drawings illustrating an embodiment thereof.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view of awellbore instrument for incorporating principles of the presentinvention;

FIG. 2 is a cross sectional view of a wellbore instrument embodying amounting in accordance with the principles of the present invention; andFIG. 3 is a sectional view taken along lines 3-3 of FIG. 2 and showing aweight and float arrangement of the apparatus.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring first to FIG. 1 ofthe drawings, a schematic view of the well survey instrument includes,at the upper end of the instrument, a power supply section 1 1 which maybe in the form of a battery pack or a power supply circuit receiving thepower from a conductor cable extending to the surface. Immediately belowthe power supply section is a control circuit housing 12 which containsthe electrical circuitry for operating the survey apparatus. Below thecontrol circuit housing is an upper instrument section 13 which isseparated from I a lower instrument section 16 by a camera section 18.The upper instrument section is shown having an inverted inclinometerunit 19 mounted therein with its indicator face 21 with scaler indiciathereon pointing downwardly away from the upper end of the tool. Agyroscopic instrument is mounted in the lower instrument section 16,having a vertical shaft 22 of the gyro instrument extending upwardlyfrom its upper end, upon which is mounted a pointer23. A circularazimuth measuring disc 24 is positioned about the pointer, and whenphotographed provides a record of the azimuth position of the toolhousing.

The camera section 18 which is located between the upper and lowerinstrument sections includes a photographic film disc 26 which isinsertable from the side of the tool through a slot (not shown). Upperand lower lens and lamp units are arranged at the ends of the camerasection. Lamps 27 at the upper end of the housing direct light on to theindicator face 21 with the resulting image being reflected through anupper lens 28 on to the top of the film disc 26. At the sametime, lamps29 at the lower end of the camera section pro vide a light source whichis reflected from the measuring disc 24 and pointer 23 in the gyrohousing through a lower lens 31 and onto the bottom of the film disc 26.Therefore, when the lamps 27, 29 are energized, images of the upper andlower instrument faces are recorded simultaneously on opposite sides ofthe film disc 26.

As set forth in the Background Of The Invention, the problems associatedwith mounting an inclinometer unit within a well tool, particularly theindicator face for high degrees of free movement, form the basis of thepresent invention. The apparatus set forth in FIGS. 2 and 3 of thedrawings is directed towards the present invention. Although theinvention is illustrated and described in detail below in itsapplication to an inverted instrument indicator, the principles thereofhave application to an upright mounting as well.

Referring now to FIG. 2, the upper instrument section is shown in detailhaving an inclinometer mounted in an inverted position therein. Theinstrument includes a housing 36 which is formed from a metal cylinderhaving an inwardly projecting shoulder portion 37 at its upper end. Thelower end of the housing is closed by a glass disc 38, which issealinglyretained over the lower end of the housing by means of a retainernut'39. A'

hemisphere shaped retainer 41 is formed in the interior of the lower endof the housing. The retainer is positioned directly above the glassdisc. An O-ring seal 42 is positioned in a peripheral groove 43 in thelower end of the retainer 41 to provide a sealing surface between theglass disc 38, the retainer nut 39, and the retainer 41. The instrumentindicator is in the form of a ball shaped float 44. A segment 46 isremoved from the upper surface of the ball in the form of a V-shapednotch. A hardened insert forms a seat 47 in the segment 46. The ballfloat 44 is made of a material which is less dense than a fluid forfilling the interior of the housing in which the instrument is located.A dense counter weight material 48 is embedded in the lower half of theball to provide a gravitational force for maintaining the ball'indicatorin itsproper orientation with respect to a horizontal reference surface.

A pivot arm 51 is positioned above the ball indicator with the lowerpointed end forming a pivot 52 received in the seat 47 of the uppersegmented surface of the indicator. The buoyancy of the fluid within theinstrument housing 36 maintains the indicator 44 against the pivot 52and leaves a space 35 filled with fluid between the indicator face 21and the hemisphere retainer 41 at the lower end of the housing.Therefore, while the counter weight 48 on the indicator ball maintainsthe indicator face in a downward direction, the buoyancy of the fluidholds the seat 47 of the indicator ball upwardly against the pivot 52.

The pivot arm 51 is slanted at an angle with respect to the center axisof the tool, and is attached by means of a lock nut 53 at its upper endto a pivot holder 54. The pivot holder is attached to the end of a shaft56 extending upwardly to the upper end of the instrument housing. Anannular shoulder portion 58 extends inwardly from the housing midwaybetween the ends of the housing. A bearing 57 is positioned within theinwardly extending shoulder portion 58 in the center of the housing, androtatably supports the shaft 56. A bearing 61 which is positioned withinthe inwardly extending shoulder 37 at the upper end of the housingrotatably supports the upper end of the shaft 56. A spacer 59 ispositioned about the shaft just above the bearing 57 and prevents adownward movement of the shaft within the bearing. Likewise, a spacer 62is positioned about the shaft just below the upper bearing 61. A counterbalance member 63 including an eccentric weight member is positionedabout the shaft between the two spacers. The counter balance member isattached to the shaft by means of a set screw 64.

A cross section of the counter balance member is shown in FIG. 3, andconsists of a lightweight plastic portion 66 and a weighted portion 67made of some metal, such as. brass. The weighted portion of the counterweight member is machined to provide a bore portion 68 for fitting aboutthe shaft. The plastic portion of the counter weight member is attachedto the weighted portion by means of screws 69 or the like.

In the operation of the wellbore surveying instrument disclosed above,the upper and lower instrument sections 13 and 16 are assembled withinthe tool housing and a timer in the electrical circuitry housing 12 isset to operate the instruments when the instruments reach a surveyingstation within the wellbore. The instrument is then lowered into thewellbore by means of a wire line or conductor cable, or is go-deviledinto drill pipe.

Once the tool has been located at a surveying station within thewellbore, the timing mechanism within the tool actuates the lamp circuitfor initiating a light source within the instrument housing. Light fromthe lamps 27, 29 impinges upon the respective lower and upper instrumentfaces and makes a photographic recording upon the film disc 26.

. During the operation of the upper instrument unit, for example, if theupper end of the inclinometer housing is tilted to the left, as viewedin FIG. 2, the weighted ball indicator 44 at the bottom of the housingis rotated to the right relative to the housing. During such relativemovement, the indicator rotates on pivot 52. Such relative rotation ortilting of the indicator to the right can take place until the indicatoris rotated approximately It is readily seen that if tilting were in theopposite direction with the members of the tool positioned as shown inFIG. 2, the ball indicator would be permitted to rotate onlyapproximately 30 before the right hand surface of the notched portion 46of the ball indicator would engage the pivot arm 51. However, since theweighted portion 67 of the counter balanced member 63 on the shaft 56 ispositioned on the opposite side of the shaft from the pivot arm 51, asthe instrument housing tilts to the right and becomes the lower side ofthe instrument, the weighted portion 67 will tend to drop downwardly tothe lower side of the housing, while the light weight plastic portion 66which is buoyant, tends to buoy upwardly. The resulting forces cause theshaft perature and pressure changes in the wellbore.

If the invention is applied to an upright mounting of the indicator 44,the same principles of operation apply. However, in such an embodimentthe ball, of

course, would be on top of the pivot. Therefore, the bottom portion ofthe ball close to the pointer would be weighted to hold the ball on thepivot with the balancing force tending to move the ball off the pivotbeing provided by the buoyant fluids. This force arrangement would bejust opposite to that shown in FIG. 1. In other respects the apparatuswould operate the same.

It is also readily seen that the invention may have application to otherwellbore devices, and therefore, while particular embodiments of thepresent invention have been shown and described, it is apparent thatchanges and modifications may be made without departing from thisinvention in its broader aspects.

What is claimed is:

1. Apparatus for indicating inclination of a wellbore comprising: ahousing; indicator means movable mounted insaid housing; pivot meansengaging said indicator means, which pivot means is angularly disposedto the vertical axis of said housing and which restricts movement ofsaid indicator means; and means responsive to changes in attitude ofsaid housing for moving said pivot means to a position which decreasesthe restriction on the movement of the indicator means.

2. The apparatus of claim 1 including a shaft and wherein the pivotmeans is attached to said shaft and wherein the pivot moving means isalso attached to said shaft.

3. The apparatus of claim 1 including a liquid in said housing andwherein the indicator means is buoyant in said liquid and retained bysaid pivot means.

4. Apparatus for indicating inclination comprising: a housing indicatormeans pivotally mounted in said housing; pivot means engaging saidindicator means and angularly disposed to the vertical axis of saidhous-v ing; and means for moving said pivot means relative to saidindicator means in response to changes in attitude of the housing.

5. The apparatus of claim 4 including a fluid in said housing andwherein the indicator means is buoyant in said fluid and retained bysaid pivot means, and wherein the indicator means includes a housingattitude change responsive portion.

6. In a wellbore instrument, the combination of means for movablymounting an indicating element of the instrument in the instrumenthousing, which means comprises: bearing means on said indicatingelement; pivot means having a pivot point engaging said bearing meansand a-pivot arm, said pivot arm being angularly disposed with respect tosaid indicating means when the housing is in a vertical position; andmeans responsive to-changes in attitude of the housing for moving saidpivot arm in a circular path within said housing.

7. The instrument of claim 6 wherein the moving means is rotatablymounted and gravity responsive and wherein the pivot arm is connected tosaid moving means so that the pivot arm is always on the opposite sideof the housing as the gravity responsive portion of the moving means.

3. In an instrument, including a housing, measuring means within saidhousing, an indicator within the housing for providing an indication ofthe measurements, means for recording the indications, an improvementfor movably mounting the indicator within the housing which comprises: apivot member for supporting the indicator for movement within thehousing;

a shaft rotatably positioned along the longitudinal axis of saidhousing; an arm member extending angularly from said shaft connected tosaid pivot member; and means responsive to changes in the angularattitude of said housing for moving said pivot member about said shaft.

9. The instrument of claim 8 including a buoyant fluid occupying thehousing, wherein the moving means includes a first weight portionconnected to said shaft opposite said arm member and a second portionbuoyant in said fluid and positioned on said shaft on approximately thesame side as said arm member.

10. In an apparatus for measuring the inclination of a wellbore: ahousing; means movable within the housing for providing indications ofchanges in the angular attitude of the housing, said indicator meansincluding an element responsive to changes in the angular attitude ofthe housing, and said indicating means having a notch portion therein;pivot means engaging the notch portion of said indicating means andangularly disposed with respect to the vertical axis of said housing;and means responsive to changes in the attitude-of said housing formoving said pivot means so said pivot means can clear the notch portionof said indicator means.

11. The apparatus of claim 10 wherein said pivot means includes a pivotpoint and a pivot arm, and further including a fluid in said housing forproviding a buoyant force to hold said indicator means in contact withsaid pivot point.

12. The apparatus of claim 11 wherein said moving means includes aweighted member acting on said pivot arm and movable in response tochanges in the attitude of the housing to move said pivot arm.

means also includes a lightweight portion which is buoyant in the fluidlocated in the housing, with the resulting buoyant force aiding saidweighted member for moving said pivot arm.

14. The apparatus of claim 10 including a buoyant fluid occupying thehousing and wherein said indicator is in the form of a lightweight ballhaving a notch therein forming a seat for said pivot member and a weightopposite said notch for maintaining a predetermined attitude of the ballin said buoyant fluid.

15. In a borehole attitudeindicating tool: a housing; an indicatingelement movable in said housing in response to changes in the attitudeof said housing;

pivot means movably mounted in 'said housing and en- 1 4 gaging saidindicating element, said pivot means having a portion thereof angularlydisposed with respect to the longitudinal axis of said housing to permittilting of said 16. Apparatus of claim 15 wherein said pivot meansincludes a seat on said indicating element and a pivot arm movablymounted in said housing, said seat having portions limiting the arcthrough which said indicating element is permitted to tilt and saidpivot arm being movable to positions for permitting tilt of saidindicating element through an are having said second maximum degree oftilt.

1. Apparatus for indicating inclination of a wellbore comprising: ahousing; indicator means movable mounted in said housing; pivot meansengaging said indicator means, which pivot means is angularly disposedto the vertical axis of said housing and which restricts movement ofsaid indicator means; and means responsive to changes in attitude ofsaid housing for moving said pivot means to a position which decreasesthe restriction on the movement of the indicator means.
 2. The apparatusof claim 1 including a shaft and wherein the pivot means is attached tosaid shaft and wherein the pivot moving means is also attached to saidshaft.
 3. The apparatus of claim 1 including a liquid in said housingand wherein the indicator means is buoyant in said liquid and retainedby said pivot means.
 4. Apparatus for indicating inclination comprising:a housing indicator means pivotally mounted in said housing; pivot meansengaging said indicator means and angularly disposed to the verticalaxis of said housing; and means for moving said pivot means relative tosaid indicator means in response to changes in attitude of the housing.5. The apparatus of claim 4 including a fluid in said housing andwherein the indicator means is buoyant in said fluid and retained bysaid pivot means, and wherein the indicator means includes a housingattitude change responsive portion.
 6. In a wellbore instrument, thecombination of means for movably mounting an indicating element of theinstrument in the instrument housing, which means comprises: bearingmeans on said indicating element; pivot means having a pivot pointengaging said bearing means and a pivot arm, said pivot arm beingangularly disposed with respect to said indicating means when thehousing is in a vertical position; and means responsive to changes inattitude of the housing for moving said pivot arm in a circular pathwithin said housing.
 7. The instrument of claim 6 wherein the movingmeans is rotatably mounted and gravity responsive and wherein the pivotarm is connected to said moving means so that the pivot arm is always onthe opposite side of the housing as the gravity responsive portion ofthe moving means.
 8. In an instrument, including a housing, measuringmeans within said housing, an indicator within the housing for providingan indication of the measurements, means for recording the indications,an improvement for movably mounting the indicator within the housingwhich comprises: a pivot member for supporting the indicator formovement within the housing; a shaft rotatably positioned along thelongitudinal axis of said housing; an arm member extending angularlyfrom said shaft connected to said pivot member; and means responsive tochanges in the angular attitude of said housing for moving said pivotmember about said shaft.
 9. The instrument of claim 8 including abuoyant fluid occupying the housing, wherein the moving means includes afirst weight portion connected to said shaft opposite said arm memberand a second portion buoyant in said fluid and positioned on said shafton approximately the same side as said arm member.
 10. In an apparatusfor measuring the inclination of a wellbore: a housing; means movablewithin the housing for providing indications of changes in the angularattitude of the housing, said indicator means including an elementresponsive to changes in the angular attitude of the housing, and saidindicating means having a notch portion therein; pivot means engagingthe notch portion of said indicating means and angularly disposed withrespect to the vertical axis of said housing; and means responsive tochanges in the attitude of said housing for moving said pivot means sosaid pivot means can clear the notch portion of said indicator means.11. The apparatus of claim 10 wherein said Pivot means includes a pivotpoint and a pivot arm, and further including a fluid in said housing forproviding a buoyant force to hold said indicator means in contact withsaid pivot point.
 12. The apparatus of claim 11 wherein said movingmeans includes a weighted member acting on said pivot arm and movable inresponse to changes in the attitude of the housing to move said pivotarm.
 13. The apparatus of claim 12 wherein said moving means alsoincludes a lightweight portion which is buoyant in the fluid located inthe housing, with the resulting buoyant force aiding said weightedmember for moving said pivot arm.
 14. The apparatus of claim 10including a buoyant fluid occupying the housing and wherein saidindicator is in the form of a lightweight ball having a notch thereinforming a seat for said pivot member and a weight opposite said notchfor maintaining a predetermined attitude of the ball in said buoyantfluid.
 15. In a borehole attitude indicating tool: a housing; anindicating element movable in said housing in response to changes in theattitude of said housing; pivot means movably mounted in said housingand engaging said indicating element, said pivot means having a portionthereof angularly disposed with respect to the longitudinal axis of saidhousing to permit tilting of said indicating element through an archaving a first maximum degree of tilt relative to a vertical plane whenthe longitudinal axis of said housing is in a vertical plane; and meansresponsive to changes in the attitude of said housing for moving saidpivot means to a position to permit tilting of said indicating elementthrough an arc having a second maximum degree of tilt relative to avertical plane which second maximum degree ot tilt is greater than saidfirst maximum degree of tilt.
 16. Apparatus of claim 15 wherein saidpivot means includes a seat on said indicating element and a pivot armmovably mounted in said housing, said seat having portions limiting thearc through which said indicating element is permitted to tilt and saidpivot arm being movable to positions for permitting tilt of saidindicating element through an arc having said second maximum degree oftilt.